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The value of (z+3)(z¯+3) is equivalent to ______.

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Question

The value of `(z + 3)(barz + 3)` is equivalent to ______.

Options

  • |z + 3|2 

  • |z – 3|

  • z2 + 3

  • None of these

MCQ
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Solution

The value of `(z + 3)(barz + 3)` is equivalent to |z + 3|2 .

Explanation:

Given that: `(z + 3)(barz + 3)` 

Let z = x + yi

So `(z + 3)(barz + 3)` = (x + yi + 3)(x – yi + 3)

= [(x + 3) + yi][(x + 3) – yi]

= (x + 3)2 – y2 i2

= (x + 3)2 + y2

= |x + 3 + iy|2

= |z + 3|2

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Chapter 5: Complex Numbers and Quadratic Equations - Exercise [Page 95]

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NCERT Exemplar Mathematics Exemplar [English] Class 11
Chapter 5 Complex Numbers and Quadratic Equations
Exercise | Q 38 | Page 95

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